a theory of disaster-driven societal collapse and how to prevent it Lajos Brons ([email protected]) Nihon University, Institute of Humanities and Social Sciences, and Lakeland University, Japan Campus, Tokyo, Japan Unpublished draft paper. — Version of September 26th, 2019. abstract — One of the effects of climate change is an increase in extreme weather and natural disasters. Unless CO2 emissions are significantly reduced very soon, it is inevitable that the effects of disaster will exceed many (and ultimately all) societies’ mitigation capacity. Compounding unmitigated disaster effects will slowly but surely push a society towards collapse. Because no part of the planet is safe from the increase in natural disaster intensity and because some of the effects of disasters – such as refugees and economic decline – spill over boundaries, this will eventually lead to global societal collapse. Furthermore, just reducing CO2 emissions is insufficient to prevent this, as disaster intensity is expected to exceed mitigation capacity in some global regions within one or two decades from now. To avoid a cascade of collapse it is necessary to reverse economic globalization and decrease long-distance trade, as well as to implement a global resettlement program for the increasing number of climate refugees. key words — climate change, natural disasters, societal collapse, refugees, globalization 1. introduction There is broad consensus within climate science that CO2-induced global warming will lead to more extreme weather and an increase in the frequency and severity of natural disasters such as storms (including hurricanes and typhoons), droughts, and floods (IPCC 2014; 2018; UNDRR 2019). We are already experiencing this increase, and the situation is expected to get much worse, and to continue getting worse for many decades to come. In this paper, I will use a very simple model to show that this will inevitably lead to global societal collapse, unless appropriate preventive action is taken. The core of the model is the rather simple and obvious idea that if disasters continuously increase, while mitigation capacity does not (and cannot) keep up with that increase, then it is inevitable that there will be a point at which a society can no longer cope with disaster and starts to decline. A formal description of the model is presented in section 2, and its main implications are discussed in section 3. It is argued that refugee flows and the economic interdependence resulting from globalized trade make collapse difficult to contain, and 1 / 17 that because no part of the planet is safe from increasing natural disaster intensity, societal collapse will eventually become global. Section 4 explains the model and its implications in plain language for readers who are uncomfortable with equations. After that, section 5 looks into the difficulties in fitting the model to the real world in order to make reliable predictions, and section 6 discusses the model’s implications for the prevention of global societal collapse. What is required is a fast reduction of CO2 emissions, de-globalization, and refugee resettlement. The final section compares the model with some other models and predictions of collapse and recapitulates this paper’s main findings. 2. formal description of the model The purpose of the theoretical model is to explain the relation between natural disasters and societal collapse. It is assumed that societal collapse corresponds to a (very) high value on a scale measuring civic unrest. Hence, the main endogenous variable is civic unrest u and the main exogenous variable is disaster intensity d. Important endogenous variables in addition to u are the state of the economy e, mitigation capacity c, displacement of people r, and physical and psychological health issues h. With one exception (namely, expected economic growth g), all variables are relative to population size (of the society/country modeled), and specific to a given year. Variables without an index refer to the given year; the index “−1” refers to the previous year; and the index “n” is a placeholder that stands for some year. The delta symbol Δ means the difference in value between a year and the previous year; thus Δy = y − y−1. Most equations include a variable x to represent external effects that are outside the scope of the model, as well as a variable i to represent interaction effects between endogenous variables. All unspecified functions are assumed to be continuously increasing and close to linear. All inputs are assumed to be positively related to the output. Where necessary, a minus sign is added: if z is a function of y such that z and y are inversely related, then z = fyz(−y). As in this example, all functions are identified by a two-letter index – the first letter identifies the main input variable; the second letter the output variable. Disaster intensity d, the main exogenous variable, is a measure of the frequency and severity of natural disasters in a given society or area. It can be roughly defined as the number of people in a society or country that were affected by natural disasters in the given year, multiplied by the length of their exposure to the effects of those disasters (or that disaster) and the severity of those effects, divided by population size. It is uncontroversial among climate scientists that climate change will lead to more extreme weather and an increase in the frequency and severity of natural disasters such as storms, droughts, and floods (IPCC 2014; 2018; UNDRR 2019). This increase in the disaster intensity will continue for decades, and possibly even centuries, although it is still possible to significantly reduce the rate and extent of that increase. Nevertheless, at least on decadal timescales, it is expected that the average yearly increase in disaster intensity is greater than zero: [D] ⟨Δdn⟩ > 0 2 / 17 The social effects of natural disasters are grouped into three different kinds: economic effects, displacement of people, and a variety of broadly health-related effects including mortality. The severity of these effects depends on disaster intensity, but also on a society’s mitigation capacity c – that is, its ability to cope with disaster: to provide food and shelter to displaced people, to maintain public order, to help the sick and wounded and prevent epidemics, to repair the damage, and so forth. Mitigation capacity depends on a number of factors. For example, tightly knit communities may be much more resilient in the face of disaster, and other kinds of social capital also improve resilience (e.g. Aldrich & Meyer 2015). However, on national and larger scales, wealth is the most important determinant of a society’s ability to cope with or mitigate natural disasters. Consequently, a change in c is primarily dependent on economic growth Δe: [C] c = c−1 + fec(Δe) + xc Economic damage due to national disasters consists of two components: losses due to temporary halts and setbacks in production and distribution, and losses due to the destruction of infrastructure and economic facilities (i.e. the facilities involved in production and distribution of goods and services). Losses of the second kind can be compensated to some extent by rebuilding and repairs, and in favorable circumstances investments can even lead to a growth in economic infrastructure and facilities p. Hence, [P] Δp = − fdp(p−1, d) + fcp(p−1, c) + xp , in which “−fdp(p−1, d)” determines the loss of economic infrastructure and facilities due to disaster, and “+fcp(p−1, c)” the gains due to reconstruction, recovery, and investment. Losses depend mostly on disaster intensity d, while reconstruction and repair of disaster damage primarily depends on mitigation capacity c. The aggregate economic effect of disaster, reconstruction, and other relevant factors is modeled as follows: [E] e = g×e−1 − fde(d, e−1) + fpe(Δp, e−1) − ie + t + xe , in which g stands for “expected economic growth”, “−fde(d, e−1)” is economic damage due to temporal halts and setbacks in production, “+fpe(Δp, e−1)” is economic losses and gains due to the change in economic infrastructure and facilities Δp (which itself depends on disasters and reconstruction; see [P] above), and t represents the contribution of trade to the state of the economy. (As mentioned above, i stands for interaction effects, which will be discussed below, while x represents external effects that are outside the scope of the model.) Δe, which plays a role in [C] as well some equations below, is e − e−1. Expected economic growth g is the economic growth that the society modeled (or similar societies) could reasonably be expected to experience if it would not be hit by natural disasters in the given year, or at least not by more disasters than what used to be normal. For the past half century, the global average growth rate has been between 2% and 4% mostly (which would suggest a value for g between 1.02 and 1.04), but it dipped below 3 / 17 zero in 2009, and there has been considerable difference between countries. For the model, this does not matter much, but it complicates application to the real world. (See section 5.) Mitigation capacity c co-determines the extent of economic recovery from disasters, but plays an equally – if not even more – important role in the non-economic direct effects of natural disasters: displacement of people, and physical and psychological health-related problems. Displaced people include evacuees and refugees. (The difference between those two groups is merely one of the extent of assistance offered: evacuees are helped with food and shelter, while refugees are left to tend for themselves.) The share of displaced people in the population r depends on disaster intensity, mitigation, and migration m: [R] r = r−1 + fdr(d) − fcr(r−1, c) + ir + m + xr , in which “+fdr(d)” determines the increase in the relative number of evacuees and refugees due to disaster, “−fcr(r−1, c)” the number of displaced people who are fully (re-)integrated into society and thereby lose their “displaced” status, and m is the number of immigrating displaced people (from societies/countries other than the one modeled) minus emigrating displaced people.